In i-line resists, KrF excimer laser resists and ArF excimer laser resists, bottom portions of the resists become lower in exposure than exposed surfaces thereof, because the resists have absorption at exposure wavelengths. In the case of positive-working resists, therefore, a pattern profile called a "taper form" is generally formed.
In the case of electron beam resist or X-ray resist, however, incident electron or X-ray has a charge, and interacts with atomic nuclei and electrons of substances constituting the resists, so that the incidence of an electron beam or X-ray into a resist film is necessarily accompanied by scattering. Accordingly, with respect to an exposed area, the bottom portion becomes larger in exposure area than the surface of the resist film. For this reason, the positive-working resist has the problem that a pattern profile called a "reverse taper form" is formed.
Further, even when exposure is carried out with reduced beam diameter for resolving a fine pattern, the scattering widens the exposure area to thereby deteriorate the resolution.
Furthermore, with recent miniaturization of processed patterns, development defects have posed a serious problem, and resists having less development defects have been desired.
Furthermore, the conventional resists have a low sensitivity, which causes a problem of so-called "throughput" in the production of integrated circuits. From this standpoint, a resist having a high sensitivity as compared with the conventional electron beam or X-ray resists has been desired.